Tether compensated airborne delivery

ABSTRACT

A tether compensated unmanned aerial vehicle (UAV) is described. In one embodiment, the UAV includes a winch with a tether to lower an item from the UAV for delivery, a flight controller to control a flight path of the UAV, a tether compensation mechanism through which the tether extends, at least one sensor to identify movement in the tether, and a tether response controller. Based on movement identified in the tether, the tether response controller may determine a complementary response and direct the tether compensation mechanism to brace the tether against the movement. Thus, the tether compensation mechanism may stabilize sway or movement in the tether by moving against the sway or movement, which may help prevent the tether from undesirable swinging when lowering the item from the UAV for delivery, for example, or at other times.

BACKGROUND

The delivery of items typically includes picking and packaging theitems, providing the packaged items to a carrier for delivery, anddelivering the items. Even for small items or small numbers of items,boxes or other packages are typically transported by vehicles overroads, sometimes across long distances.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure can be better understood withreference to the following drawings. It is noted that the elements inthe drawings are not necessarily to scale, with emphasis instead beingplaced upon clearly illustrating the principles of the embodiments. Inthe drawings, like reference numerals designate like or corresponding,but not necessarily the same, elements throughout the several views.

FIG. 1A illustrates a perspective view of an example tether compensatedunmanned aerial vehicle (UAV) according to one embodiment of the presentdisclosure.

FIG. 1B illustrates a perspective view of the tether compensated UAV inFIG. 1A with an alternative tether compensation mechanism accordinganother embodiment of the present disclosure.

FIG. 2 illustrates a block diagram of components of the tethercompensated UAV in FIGS. 1A and 1B according to various embodiments ofthe present disclosure.

FIG. 3A illustrates a tether compensation mechanism of the UAV in FIG.1A according to one embodiment of the present disclosure.

FIG. 3B illustrates a tether compensation mechanism of the UAV in FIG.1B according to another embodiment of the present disclosure.

FIG. 4 illustrates a flow diagram of an example process of tethercompensated airborne delivery.

FIG. 5 illustrates an example schematic block diagram of the computingdevice employed in the tether compensated UAV in FIG. 2 according tovarious embodiments of the present disclosure.

DETAILED DESCRIPTION

Embodiments of a tether compensated unmanned aerial vehicle (UAV) aredescribed. In this regard, FIG. 1A illustrates a perspective view of anexample tether compensated UAV 100 according to one embodiment of thepresent disclosure. The UAV 100 includes a frame body housing 102 havingarms that support motors 110-113. Propellers are attached to the motors110-113 to provide thrust for flight of the UAV 100. A camera 104 may beprovided on an exterior of the frame body housing 102. The camera 104may include one or more image sensors and be relied upon for monitoringthe height of the UAV 100, navigating the UAV 100, and other purposesdescribed herein. The UAV 100 also includes at least one winch 130. Asillustrated, the winch 130 is wound with a tether 132 which may beextended down from the winch 130. When an item 140 is attached to theextendable end of the tether 132, the winch 130 may be relied upon toraise or lower the item 140 for transport and delivery.

In operation, the UAV 100 may be used to provide airborne delivery ofitems, packages, parcels, etc. That is, after the item 140 is secured tothe tether 132 using a suitable attachment mechanism, the UAV 100 maytravel by flight to a delivery zone 170. While travelling, the item 140may be raised by the winch 130 and maintained in a retracted position.When the UAV 100 is positioned in flight above the delivery zone 170,the tether 132 and attached item 140 may be extended or lowered downfrom the UAV 100 by the winch 130 and the item 140 released at thedelivery zone 170.

Rather than landing the UAV 100 at the delivery zone 170 beforereleasing the item 140, various advantages may be realized by using thewinch 130 to lower the item 140 toward the landing surface at thedelivery zone 170 before it is released. For example, it may be moreenergy efficient to maintain the UAV 100 at a minimum height above thelanding surface when delivering the item 140, rather than landing theUAV 100. Further, it may be safer for the UAV 100 and/or individualsnear the delivery zone 170 to maintain the UAV 100 at a minimum heightabove the landing surface when delivering the item 140.

The use of the winch 130 to lower the item 140 from the UAV 100 may giverise to certain operating considerations, such as the potential forflight instability for the UAV 100, the potential for undesirablemovement, sway, or oscillations in the tether 132 and the item 140, thepotential for unexpected swing in the tether 132, etc. At least some ofthese operating considerations may be attributed to movement experiencedin the tether 132, at least some of which may be translated through thewinch 130 to the UAV 100.

Movement in the tether, as described herein, may be caused by airresistance against the tether 132 and/or the item 140, wind, rain, hail,or other meteorological factors, changes in speed and/or direction ofthe UAV 100 which tend to shift the momentum of the tether 132 and/orthe item 140, and other external forces or factors and combinationsthereof. The movement may include one or a combination of lateralmovement (e.g., “X” and “Y”) and/or vertical tension (e.g., “Z”)components of motion and/or force, as illustrated by the dotted lines inFIG. 1A.

In view of these and other considerations, the UAV 100 includes a tethercompensation mechanism 150A. As described in further detail below, thetether compensation mechanism 150A may be relied upon to brace thetether 132 against vertical motion experienced in the tether 132. Inthat sense, the tether compensation mechanism 150A may grab, grip,pinch, or clamp the tether 132 to hold and prevent it from pullingfurther away from the winch 130 and the UAV 100. In that context, arepresentative grabbing or gripping motion by the tether compensationmechanism 150A is indicated at reference “A” in FIG. 1A.

The tether compensation mechanism 150A may also be relied upon tocompensate for lateral motion experienced in the tether 132. In thatsense, the tether compensation mechanism 150A may actuate or move tocompensate for motion detected in the tether 132. In other words, thetether compensation mechanism 150A may stabilize sway or movement in thetether 132 by moving against the sway, which may prevent the tether 132from undesirable swinging, for example. In that context, arepresentative compensating motion is indicated at reference “B” in FIG.1A.

Thus, as further described below, the use of the tether compensationmechanism 150A in combination with the winch 130 may help to avoidflight instability for the UAV 100, the potential for undesirable swayor oscillations in the tether 132 and the item 140, and other conditionswhich may prevent the UAV 100 from safely delivering the item 140 to thedelivery zone 170.

FIG. 1B illustrates a perspective view of the tether compensated UAV 100in FIG. 1A with an alternative tether compensation mechanism 150Baccording another embodiment of the present disclosure. As compared tothe tether compensation mechanism 150A in FIG. 1A, the tethercompensation mechanism 150B may be capable of grabbing, gripping, andcompensating motions similar to the motions “A” and “B” in FIG. 1A, butusing a different mechanical structure. The tether compensationmechanisms 150A in FIGS. 1A and 150B in FIG. 1B are described in detailbelow with reference to FIGS. 3A and 3B, respectively.

Before turning to FIG. 2, it is noted that the UAV 100 in FIGS. 1A and1B is provided as a representative example only, is not drawn to scale,and is not intended to be limiting with regard to the type, structure,or scope of the embodiments described herein. Similarly, in FIGS. 1A and1B, the size, structure, and arrangement of the parts of the tethercompensation mechanisms 150A and 150B are representative of embodimentsof mechanisms to compensate for certain operating conditions which mayarise due to use of the winch 130, and alternative embodiments arewithin the scope of the embodiments.

FIG. 2 illustrates a block diagram of components of the tethercompensated UAV 100 in FIGS. 1A and 1B according to various embodimentsof the present disclosure. The UAV 100 includes the frame 102, a rotorsystem 210, the winch 130 secured to an underside of the UAV 100, thetether 132 of the winch 130, an attachment mechanism 234 at one end ofthe tether 132, the tether compensation mechanism 150, a computingdevice 260, and a tension detector 290. The UAV 100 may be relied uponto deliver the item 140 as described herein.

As illustrated, the computing device 260 includes a flight control datastore 270, a flight controller 280, one or more flight sensors 284, anda communications interface 286. The flight control data store 270includes flight control data 272 and delivery data 274, and the flightcontroller 280 includes a flight control processor 281, a winchcontroller 282, and a tether response controller 283.

As with the illustrations in FIGS. 1A and 1B, the block diagram of theUAV 100 in FIG. 2 is not drawn to scale or to be limiting with regard tostructural connections between components or relative structuralarrangements between them. Instead, the block diagram provides arepresentative outline of various components that may be relied upon intether compensated UAVs. Further, the block diagram of the UAV 100 inFIG. 2 is not exhaustive as to the components or parts of the UAV 100.That is, the UAV 100 may include other components, such as one or morebatteries, fuel tanks, communications and/or control systems, etc.,which are omitted for the sake of focus. Finally, not every component inFIG. 2 is required in all embodiments. In other words, one or morecomponents illustrated in FIG. 2 may be omitted.

The rotor system 210 may include one or more motors, engines, etc., suchas the motors 110-113 in FIGS. 1A and 1B, with attached propellers thatprovide thrust for flight of the UAV 100. Among embodiments, anysuitable type and number of motors, engines, etc. may be relied upon toprovide thrust for flight, depending upon considerations such as thesize of the UAV 100, the weight of the item 140, the distance the UAV100 must travel for delivery of the item 140, or other considerations.The rotor system 210 and, hence, the flight of the UAV 100 arecontrolled by the computing device 260 of the UAV 100, as describedherein.

The winch 130 may be embodied as one or more winches similar to thewinch 130 in FIGS. 1A and 1B, for example, or other types of winches.Generally, the winch 130 may be embodied as a mechanical device thatextends and retracts the tether 132, the attachment mechanism 234 and,when attached, the item 140. In this context, the winch 130 may includea spool or drum for winding the tether 132 and gear assemblies poweredby an electric motor, such as a stepper or continuous servo motor, forexample, for turning or rotating the spool to extend or retract thetether 132. Among other means, the winch 130 may be secured to the frame102 of the UAV 100 using any suitable attachment means, such as screws,bolts, clips, adhesives, or combinations thereof.

In various embodiments, the tether 132 may be embodied as one or moreflexible, semi-flexible, or rigid string, rope, wire, chain, drag chain,extension spring, or other suitable types of tethers. The attachmentmechanism 234 may be embodied as any suitable attachment mechanism ormeans at one end of the tether 132 for releasably securing the item 140to the tether 132. For example, the attachment mechanism 234 may beembodied as a releasable clamp, grip, claw, or hook. In such case, theattachment mechanism 234 may be adjustable to secure various sizes ofitems, packages, parcels, etc. to the tether 132. As other examples, theattachment mechanism 234 may be embodied as one or more magnets,electromagnets, electro-permanent magnets, solenoid latches, etc.

If an electromagnet is relied upon as the attachment mechanism 234, theelectromagnet may be powered or actuated to hold the item 140. Whenpower to the electromagnet is cut off, the electromagnet may bedemagnetized and release the item 140. If an electro-permanent magnet isrelied upon, a permanent magnet may hold the item 140. When power isprovided to the electro-permanent magnet, current that flows through theelectro-permanent magnet may demagnetize, oppose, or overcome themagnetization of the permanent magnet and release the item 140. Itshould be appreciated that other attachment mechanisms are within thescope of the embodiments, including various combinations of themechanisms described above. In the UAV 100, the winch controller 282 isconfigured to control the attachment mechanism 234 to secure and/orrelease the item 140 based on various considerations and/or controlinputs as described below.

The tether compensation mechanism 150 illustrated in FIG. 2 includes atleast one extension arm 252 including an actuator 256, an aperturemechanism 254 positioned proximate to an end of the extension arm 252,and a sensor 258 that identifies movement in the tether 132 based oncontact between the tether 132 and the aperture mechanism 254 (e.g., dueto movement in the tether 132). In some embodiments, the tethercompensation mechanism 150 also includes a sensor 259 that identifiesmovement in the tether 132 based on movement in the attachment mechanism234, which is also representative of movement in the item 140 at the endof the tether.

As shown in FIG. 2, the tether 132 extends or passes through theaperture mechanism 254, and the tether 132 may make mechanical orphysical contact with the aperture mechanism 254. At least to someextent, contact between the tether 132 and the aperture mechanism 254may be directed or controlled by the tether response controller 283 tocompensate for or otherwise respond to movement in the tether 132. Thiscompensation for or response to movement in the tether 132 may prevent,eliminate, or reduce undesirable movement, sway, or oscillations in thetether 132 and the item 140, for example, or otherwise help the UAV 100to maintain a desired flight path or position.

Movement in the tether 132 may be identified (e.g., sensed) by thesensors 258 and 259 and, in some cases, by the tension detector 290,which is described in further detail below. In the embodimentillustrated in FIG. 2, the sensor 258 is mounted on the aperturemechanism 254, although it may be mounted at other locations on the UAV100, such the frame 102. The sensor 259 is mounted on the attachmentmechanism 234, although it may be mounted at other locations, such onthe item 140. The sensors 258 and 259 may be embodied as one or moremicro- or nano-electromechanical system (NEMS or MEMS) or other type ofmotion, accelerometer, gyroscope, or similar sensors. The sensors 258and 259 may also include one or more contact or pressure sensors.

As noted above, because the tether 132 extends or passes through theaperture mechanism 254, if the tether 132 experiences motion that causesit to move, sway, or swing laterally against the aperture mechanism 254,the sensor 258 may identify a magnitude and direction of force ormovement attributed to the sway or swing. In other words, the sensor 258may be configured to identify at least one component (e.g.,magnitude(s), direction(s), or magnitude(s) and direction(s)) of forceor movement in the tether 132. Similarly, the sensor 259 may beconfigured to identify at least one component (e.g., magnitude(s),direction(s), or magnitude(s) and direction(s)) of movement in theattachment mechanism 234. In turn, the sensors 258 and 259 may providecontrol signals to the tether response controller 283 which arerepresentative of the at least one component of the movement or force inthe tether 132. In response, the tether response controller 283 isconfigured to determine a complementary response to the movement orforce in the tether 132 and direct or control the tether compensationmechanism 150 as further described below. Similarly, if the tether 132experiences motion that tends to cause the item 140 to move, sway, orswing laterally, the sensor 259 may identify a movement in theattachment mechanism 234 that is attributed to the movement.

The computing device 260 may be embodied, at least in part, as one ormore embedded or general-purpose processors, computers, processingdevices, or computing devices having memory. The computing device 260may also be embodied, in part, as various functional and/or logic (e.g.,computer-readable instruction, code, device, circuit, processingcircuit, etc.) elements executed or operated to perform aspects of theembodiments described herein. The computing device 260 may be mountedand secured within the frame 102 of the UAV 100.

As noted above, the flight control data store 270 includes flightcontrol data 272 and delivery data 274. The flight control data 272 mayinclude any data necessary to control the flight of the UAV 100, such asoperations and/or control algorithms, flight reference data, etc. Thedelivery data 274 may include any data necessary for the delivery of oneor more items, such as map or coordinate system data, address data,scheduling and/or delivery protocol data, etc.

With regard to the flight controller 280, the flight control processor281 is configured to control the flight and flight path of the UAV 100for delivery of the item 140, for example, and to perform other tasks.The winch controller 282 is configured to control or actuate the winch130 to extend and retract the tether 132 at certain times and based oncertain considerations. The winch controller 282 is also configured torelease the attachment mechanism 234 based on certain considerationsdescribed below.

The tether response controller 283 is configured to receive a controlsignal representative of at least one component of movement, force, ortension in the tether 132. Using the control signal as input, the tetherresponse controller 283 is further configured to determine acomplementary response to the movement, force, or tension and direct thetether compensation mechanism 150 based on the complementary response.

For example, after determining a complementary response to movement inthe tether 132, the tether response controller 283 may direct the tethercompensation mechanism 150 to brace against or compensate for themovement in an amount proportional to the complementary response. As oneresponse, for example, the tether response controller 283 may direct theaperture mechanism 254 to grab, grip, pinch, or clamp the tether 132 tohold and prevent it from pulling further away from the winch 130. Thistype of response may be appropriate when an unexpected and relativelyhigh amount of tension is experienced on the tether 132.

As another example response, the tether response controller 283 maydirect the extension arm actuator 256 to actuate or move the extensionarm 252 to counterbalance against or compensate for movement or swaydetected in the tether 132. That is, the aperture mechanism 254 may beshifted to contact the tether 132 and stabilize the sway or movement init. Such stabilization may prevent, eliminate, or reduce undesirableswinging, for example, in the tether 132. This type of response may beappropriate when the flight path of the UAV 100 changes or when windcauses the tether 132 to move or sway.

In various embodiments, the tether response controller 283 may operatein conjunction with or independently from the flight control processor281 and/or the winch controller 282. For example, the tether responsecontroller 283 may be configured to control the tether compensationmechanism 150 without communicating with the flight control processor281 and/or the winch controller 282. Even in this situation, it shouldbe appreciated that any undesirable movement that occurs in the tether132 which is translated (i.e., passed on) to the UAV 100 may be detectedby and compensated for by the flight sensors 284 and the flight controlprocessor 281.

In other embodiments, the tether response controller 283 may beconfigured to control the tether compensation mechanism 150 based on orwith reference to flight and winch control data from the flight controlprocessor 281 and the winch controller 282. For example, the tetherresponse controller 283 may determine a complementary response tomovement in the tether 132 based on a current or expected flight path ofthe UAV 100. As another example, the tether response controller 283 mayreceive an indication of change in the flight path of the UAV 100 fromthe flight control processor 281, before the change occurs. The tetherresponse controller 283 may then determine a complementary response tothe change in the flight path and direct the tether compensationmechanism 150 accordingly. This feed-forward control of the tethercompensation mechanism 150 (i.e., before flight path changes of the UAV100 occur) may help to avoid undesirable or unexpected swinging in thetether 132. Alternatively, rather than (or in addition to) directing thetether compensation mechanism 150, the tether response controller 283may direct the flight control processor 281 to make adjustments in theflight path of the UAV 100 to avoid movement or swing conditions in thetether 132.

As still another example, the tether response controller 283 may receivean indication as to whether the winch 130 is extending or retracting thetether 132. In that case, the tether response controller 283 maydetermine a complementary response based at least in part on whether thetether 132 is extending from or retracting to the winch 130 and/or thelength of extension of the tether 132 from the winch 130.

The flight sensors 284 may include one or more NEMS, MEMS, or othertypes of motion, accelerometer, gyroscope, or similar sensors. Theflight sensors 284 may also include one or more global positioningsystem (“GPS”) sensors, height, altitude, or altimeter sensors, anultrasonic sensor, a pressure sensor, and/or image, infrared, or thermalsensors (i.e., various types of cameras) (e.g., the camera 104 in FIGS.1A and 1B), among others. The flight sensors 284 may provide geographic,navigation, and/or orientation signals to the flight controller 280. Incertain embodiments, one or both of the sensors 258 and 259 may beomitted and the sensing functions of the sensors 258 and 259 may beperformed by the flight sensors 284.

The communications interface 286 may include any suitable interface forcommunicating data, such as a cellular interface (e.g., Global Systemfor Mobile communications (“GSM”), Code Division Multiple Access(“CDMA”), Local Multi-point Distribution Systems (“LMDS”), Long TermEvolution (“LTE”), Multi-channel-Multi-point Distribution System(“MMDS”), etc.), a Bluetooth interface, a Wireless Local Area Network(“WLAN”) (e.g., 802.11-based) interface, or any combination thereof,among other communications interfaces.

As illustrated in FIG. 2, the tension detector 290 may be interposedbetween the winch 130 and the frame 102 of the UAV 100. The tensiondetector 290 may be embodied as a sensor that detects an amount ofvertical tension, weight, or load on the tether 132. The tensiondetector 290 may also provide a control signal representative of thatamount of tension to the computing device 260.

In some embodiments, the tension detector 290 may break or disconnectautomatically under a predetermined amount of tension. In that context,the tension detector 290 may be embodied as one or more attachmentstructures (e.g., screws, buts, bolts, clips, etc.) of limited tensilestrength. In such case, if an unexpected level of tension arises in thetether 132, the tension detector 290 may automatically break ordisconnect the winch 130 from the frame 102.

In other embodiments, the tension detector 290 may break or disconnectin response to a control signal from the computing device 260. That is,the tension detector 290 may be controlled by the computing device 260to release or disconnect the winch 130 from the frame 102 based on anamount of tension detected by tension detector 290. In this case, thetension detector 290 may be embodied as some type of exploding,fracturing, or pyrotechnic attachment structure that releases inresponse to a control signal from the computing device 260. Thus, if anunexpected level of tension (e.g., greater than a predetermined amount)arises, the tension detector 290 may detect and provide a control signalrepresentative of that tension to the computing device 260. In turn, thecomputing device 260 may control the tension detector 290 (and/or theattachment mechanism 234) to disconnect. In this sense, the tensiondetector 290 offers some protection against the tether 132 beingunexpectedly pulled or caught in a tree, power line, etc.

FIG. 3A illustrates the tether compensation mechanism 150A of the UAV100 in FIG. 1A. The tether compensation mechanism 150A includes theextension arm 252A, the aperture mechanism 254, and the extension armactuator 256. The extension arm actuator 256 is mounted between one endof the extension arm 252A and the frame 102, and the aperture mechanism254 is mounted proximate to another end of the extension arm 252A. Thetether compensation mechanism 150A also includes the sensor 258 thatidentifies movement in the tether 132 based on physical contact betweenthe tether 132 and the aperture mechanism 254, and the sensor 259 thatidentifies movement in the tether 132 based on movement in theattachment mechanism 234 (FIG. 2).

As shown in FIG. 3A, the tether compensation mechanism 150A is designedto provide at least some movement in one or more of the “X,” “Y,” and“Z” directions based on control signals from the tether responsecontroller 283. To that end, the extension arm 252A may be embodied asan adjustable-length telescoping arm, and the extension arm actuator 256may be embodied as various electromechanical systems (e.g., motors,servos, solenoids, etc.) capable of moving the extension arm 252A. Thetether response controller 283 may direct the extension arm actuator 256and the extension arm 252A to move the attachment mechanism 234, makecontact with the tether 132, and counterbalance against or compensatefor movement or sway detected in the tether 132. In one embodiment, theaperture mechanism 254 may include rollers 355 that surround or encirclethe tether 132, although it is not necessary that the aperture mechanism254 completely encircle the tether 132 in every embodiment. The rollers355 include a clearance through which the tether 132 extends. Therollers 355 may be controlled by the tether response controller 283 topress together. In that case, the rollers 355 may grab, grip, pinch, orclamp the tether 132 to hold and prevent it from pulling further awayfrom the winch 130 and the UAV 100.

FIG. 3B illustrates the tether compensation mechanism 150B of the UAV100 in FIG. 1B according to another embodiment of the presentdisclosure. The tether compensation mechanism 150B includes theextension arms 252B and 252C and the aperture mechanism 254. Theaperture mechanism 254 is mounted proximate to ends of the extensionarms 252B and 252C, and the other ends of the extension arms 252B and252C are mounted to the frame 102. The tether compensation mechanism150B also includes the sensor 258 that identifies movement in the tether132 based on physical contact between the tether 132 and the aperturemechanism 254, and the sensor 259 that identifies movement in the tether132 based on movement in the attachment mechanism 234 (FIG. 2).

As shown in FIG. 3B, the tether compensation mechanism 150B is designedto provide at least some movement in at least the “X” and “Y” directionsbased on control signals from the tether response controller 283. Tothat end, the extension arms 252B and 252C may be embodied as anadjustable-length telescoping arms and electromechanical systems (e.g.,motors, servos, solenoids, etc.) capable of adjusting the angles of theextension arms 252B and 252C at the pivots points 253B and 253C. Thetether response controller 283 may direct the extension arms 252B and252C and the pivots points 253B and 253C to move the aperture mechanism254, make contact with the tether 132, and counterbalance against orcompensate for movement or sway detected in the tether 132.

For additional details regarding the operation of the UAV 100 in FIGS.1, 2, 3A, and 3B, FIG. 4 illustrates a flow diagram of an exampleprocess 400 of tether compensated airborne delivery that may beperformed by the UAV 100. While the process 400 is described inconnection with the UAV 100, it should be appreciated that the process400 may be performed by other UAVs. It should also be noted that theflowchart in FIG. 4 provides merely one example of a process that may beemployed for tether compensated airborne delivery.

At reference numeral 402, the process 400 includes navigating a flightpath of the UAV 100 to deliver the item 140 (FIG. 2). Here, it isassumed that the UAV 100 has picked up the item 140 for delivery, andthat the item 140 is secured to the tether 132 by way of the attachmentmechanism 234. The flight controller 280 is configured to reference anydata necessary in the flight control data 272 and/or the delivery data274 for navigation and control of the rotor system 210 to direct the UAV100 to a predetermined delivery zone for the item 140. The predetermineddelivery zone may be identified by an address, street location,geographic coordinates, or other identifying information. Whilenavigating, the flight control processor 281 may reference data providedby the flight sensors 284, such as GPS coordinates, image information,etc., to locate the delivery zone.

When the UAV 100 is proximate to the delivery zone, the process 400includes positioning the UAV 100 over the delivery zone to deliver theitem 140, at reference numeral 404. The delivery zone may be marked withsome visual marking, as the delivery zone 170 in FIGS. 1A and 1B ismarked with crosshairs, for example. When visually marked, the UAV 100may rely upon an image sensor among the flight sensors 284, for example,to narrow in on the delivery zone at reference numeral 404 (e.g., usingimage processing).

Once the UAV 100 is positioned over the delivery zone, at referencenumeral 406, the process 400 includes actuating the winch 130 to lowerthe tether 132. More particularly, the winch controller 282 may actuatethe winch 130 to extend the tether 132 down and lower the item 140 fordelivery. The use of the winch 130 to lower the item 140 from the UAV100 may raise the potential for flight instability for the UAV 100, thepotential for undesirable sway or oscillations in the tether 132 and theitem 140, the potential for unexpected forces on the tether 132, etc.

Thus, at reference numeral 408, the process 400 includes identifying, byone or more of the sensors 258 and 259, for example, at least onecomponent of movement or force in the tether 132. As discussed above,the sensor 258 may identify or measure lateral movement or forces in thetether 132 based on physical contact between the tether 132 and theaperture mechanism 254. Further, the sensor 259 may identify movement inthe tether 132 due to movement in the attachment mechanism 234. In turn,the sensors 258 and 259 may provide one or more control signals that arerepresentative of the movement or force in the tether 132 to the tetherresponse controller 283.

In some embodiments, at reference numeral 408, the process 400 may alsoinclude identifying tension in the tether 132 using by the tensiondetector 290. The tension detector 290 may identify vertical force ortension (i.e., weight, load, etc.) in the tether 132 and provide asignal representative of such tension to the tether response controller283. As described in further detail below, the tether responsecontroller 283 may monitor for vertical tension greater than apredetermined threshold or greater than that expected for the weight ofthe item 140, for example.

At reference numeral 410, the process 400 includes the tether responsecontroller 283 determining a response to the movement or forceidentified at reference numeral 408. In this context, the tetherresponse controller 283 may determine that it is necessary to grab,grip, pinch, or clamp the tether 132 to prevent it from pulling furtheraway from the winch 130. This type of response may be appropriate whenan unexpected and relatively high amount of vertical or lateral movementis experienced on the tether 132. As another example, the tetherresponse controller 283 may determine a complementary, proportionalresponse to vertical or lateral components of movement or forceidentified at reference numeral 408. This type of response may beappropriate when the flight path of the UAV 100 changes or when windcauses the tether 132 to sway.

At reference numeral 412, the process 400 includes the tether responsecontroller 283 directing the tether compensation mechanism 150 to bracethe tether 132 against the movement in the tether 132 according to theresponse determined at reference numeral 410. In this context, thetether response controller 283 may direct the aperture mechanism 254 tograb the tether 132 or direct the extension arm actuator 256 tocounterbalance against movement or sway detected in the tether 132. Inthat way, the aperture mechanism 254 may be shifted to contact thetether 132 and stabilize the movement or sway in it. Such stabilizationmay prevent, eliminate, or reduce undesirable swinging, for example, inthe tether 132. This type of response may be appropriate when the flightpath of the UAV 100 changes or when wind causes the tether 132 to sway.

At reference numeral 414, the process 400 may include the flight controlprocessor 281 adjusting or stabilizing the fight path of the UAV 100.That is, during and after the winch controller 282 lowers the tether132, the flight control processor 281 is configured to direct the flightand/or maintain an orientation of the UAV 100. In this context, theflight control processor 281 may receive feedback from both the flightsensors 238 and the tether response controller 283 when adjusting orstabilizing the fight path of the UAV 100. Thus, the flight controlprocessor 281 may make adjustments, in part, based on the complementaryresponse to the movement determined at reference numeral 410. Further,the flight control processor 281 may provide an indication of change inthe flight path of the UAV 100 to the tether response controller 283, asfeed forward information. The tether response controller 283 may usethis information to determine the appropriate response to control thetether compensation mechanism 150.

At reference numeral 416, the process 400 includes determining whetherthe UAV 100 is ready to drop the item 140. Here, the winch controller282 may consider various factors before directing the attachmentmechanism 234 to release the item 140. For example, the winch controller282 may consider whether the orientation of the UAV 100 is stable enoughand/or whether any movement in the tether 132 is small enough to releasethe item 140 at reference numeral 416. Also, the winch controller 282may determine whether the height of the UAV 100 is suitable forreleasing the item 140. In some cases, the winch controller 282 maydetermine whether the height of the UAV 100 is less than a predeterminedheight before releasing the item 140. If the height of the UAV 100 istoo great, the winch controller 282 may determine that the UAV 100 isnot low enough to safely release the item 140, and the process 400 mayproceed to reference numeral 420.

At reference numeral 420, the process 400 includes determining whetherthe tension in the tether 132 is too high for safe operation of the UAV100. In other words, at reference numeral 420, the process 400 includesdetermining whether the tension is greater than a predeterminedthreshold or greater than that expected for the weight of the item 140,for example. For example, the tension detector 290 may detect thetension and provide a signal representative of it to the tether responsecontroller 283. The tether response controller 283 may determine whetherthe tension is greater than a predetermined threshold. If so, theprocess 400 proceeds to reference numeral 422, for disconnecting theitem 140 from the UAV 100. Particularly, the tether response controller283 may control the tension detector 290 to disconnect the winch 130from the UAV 100. If disconnected, the winch 130 may fall from the UAV100 along with the item 140. In this sense, the tension detector 290offers some protection against the tether 132 or the item 140 beingunexpectedly pulled or caught in a tree, power line, etc.

FIG. 5 illustrates an example schematic block diagram of the computingdevice 260 employed in the tether compensated UAV 100 in FIGS. 1-3according to various embodiments of the present disclosure. Thecomputing device 260 includes one or more computing devices 500. Eachcomputing device 500 includes at least one processing circuit or system,for example, having a processor 502 and a memory 504, both of which areelectrically and communicatively coupled to a local interface 506. Thelocal interface 506 may be embodied as, for example, a data bus with anaccompanying address/control bus or other bus structure as can beappreciated.

In various embodiments, the memory 504 stores data and software orexecutable-code components executable by the processor 502. For example,the memory 504 may store executable-code components associated with theflight controller 280, for execution by the processor 502. The memory504 may also store data such as that stored in the flight control datastore 270, among other data.

The memory 504 may store other executable-code components for executionby the processor 502. For example, an operating system may be stored inthe memory 504 for execution by the processor 502. Where any componentdiscussed herein is implemented in the form of software, any one of anumber of programming languages may be employed such as, for example, C,C++, C#, Objective C, JAVA®, JAVASCRIPT®, Perl, PHP, VISUAL BASIC®,PYTHON®, RUBY, FLASH®, or other programming languages.

As discussed above, in various embodiments, the memory 504 storessoftware for execution by the processor 502. In this respect, the terms“executable” or “for execution” refer to software forms that canultimately be run or executed by the processor 502, whether in source,object, machine, or other form. Examples of executable programs include,for example, a compiled program that can be translated into a machinecode format and loaded into a random access portion of the memory 504and executed by the processor 502, source code that can be expressed inan object code format and loaded into a random access portion of thememory 504 and executed by the processor 502, source code that can beinterpreted by another executable program to generate instructions in arandom access portion of the memory 504 and executed by the processor502, etc. An executable program may be stored in any portion orcomponent of the memory 504 including, for example, a random accessmemory (RAM), read-only memory (ROM), magnetic or other hard disk drive,solid-state, semiconductor, or similar drive, universal serial bus (USB)flash drive, memory card, optical disc (e.g., compact disc (CD) ordigital versatile disc (DVD)), floppy disk, magnetic tape, or othermemory component.

In various embodiments, the memory 504 may include both volatile andnonvolatile memory and data storage components. Volatile components arethose that do not retain data values upon loss of power. Nonvolatilecomponents are those that retain data upon a loss of power. Thus, thememory 504 may include, for example, a RAM, ROM, magnetic or other harddisk drive, solid-state, semiconductor, or similar drive, USB flashdrive, memory card accessed via a memory card reader, floppy diskaccessed via an associated floppy disk drive, optical disc accessed viaan optical disc drive, magnetic tape accessed via an appropriate tapedrive, and/or other memory component, or any combination thereof. Inaddition, the RAM may include, for example, a static random accessmemory (SRAM), dynamic random access memory (DRAM), or magnetic randomaccess memory (MRAM), and/or other similar memory device. The ROM mayinclude, for example, a programmable read-only memory (PROM), erasableprogrammable read-only memory (EPROM), electrically erasableprogrammable read-only memory (EEPROM), or other similar memory device.

Also, the processor 502 may represent multiple processors 502 and/ormultiple processor cores and the memory 504 may represent multiplememories that operate in parallel, respectively, or in combination.Thus, the local interface 506 may be an appropriate network or bus thatfacilitates communication between any two of the multiple processors502, between any processor 502 and any of the memories 504, or betweenany two of the memories 504, etc.

As discussed above, the flight controller 280 may be embodied, in part,by software or executable-code components for execution by generalpurpose hardware. Alternatively, the same may be embodied in dedicatedhardware or a combination of software, general, specific, and/ordedicated purpose hardware. If embodied in such hardware, each can beimplemented as a circuit or state machine, for example, that employs anyone of or a combination of a number of technologies. These technologiesmay include, but are not limited to, discrete logic circuits havinglogic gates for implementing various logic functions upon an applicationof one or more data signals, application specific integrated circuits(ASICs) having appropriate logic gates, field-programmable gate arrays(FPGAs), or other components, etc. Such technologies are generally wellknown by those skilled in the art and, consequently, are not describedin detail herein.

The flowchart or process diagram of FIG. 4 is representative of certainprocesses, functionality, and operations of embodiments discussedherein. Each block may represent one or a combination of steps orexecutions in a process. Alternatively or additionally, each block mayrepresent a module, segment, or portion of code that includes programinstructions to implement the specified logical function(s). The programinstructions may be embodied in the form of source code that includeshuman-readable statements written in a programming language or machinecode that includes numerical instructions recognizable by a suitableexecution system such as the processor 502. The machine code may beconverted from the source code, etc. Further, each block may represent,or be connected with, a circuit or a number of interconnected circuitsto implement a certain logical function or process step.

Although the flowchart or process diagram of FIG. 4 illustrates aspecific order, it is understood that the order may differ from thatwhich is depicted. For example, an order of execution of two or moreblocks may be scrambled relative to the order shown. Also, two or moreblocks shown in succession in FIG. 4 may be executed concurrently orwith partial concurrence. Further, in some embodiments, one or more ofthe blocks shown in FIG. 4 may be skipped or omitted. In addition, anynumber of counters, state variables, warning semaphores, or messagesmight be added to the logical flow described herein, for purposes ofenhanced utility, accounting, performance measurement, or providingtroubleshooting aids, etc. It is understood that all such variations arewithin the scope of the present disclosure.

Also, any logic or application component described herein, such as theflight controller 280 that is embodied, at least in part, by software orexecutable-code components, may be embodied or stored in any tangible ornon-transitory computer-readable medium or device for execution by aninstruction execution system such as a general purpose processor. Inthis sense, the logic may be embodied as, for example, software orexecutable-code components that can be fetched from thecomputer-readable medium and executed by the instruction executionsystem. Thus, the instruction execution system may be directed byexecution of the instructions to perform certain processes such as thoseillustrated in FIG. 4. In the context of the present disclosure, a“computer-readable medium” can be any tangible medium that can contain,store, or maintain any logic, application, software, or executable-codecomponent described herein for use by or in connection with aninstruction execution system.

The computer-readable medium can include any physical media such as, forexample, magnetic, optical, or semiconductor media. More specificexamples of suitable computer-readable media include, but are notlimited to, magnetic tapes, magnetic floppy diskettes, magnetic harddrives, memory cards, solid-state drives, USB flash drives, or opticaldiscs. Also, the computer-readable medium may include a RAM including,for example, an SRAM, DRAM, or MRAM. In addition, the computer-readablemedium may include a ROM, a PROM, an EPROM, an EEPROM, or other similarmemory device.

Although embodiments have been described herein in detail, thedescriptions are by way of example. The features of the embodimentsdescribed herein are representative and, in alternative embodiments,certain features and elements may be added or omitted. Additionally,modifications to aspects of the embodiments described herein may be madeby those skilled in the art without departing from the spirit and scopeof the present invention defined in the following claims, the scope ofwhich are to be accorded the broadest interpretation so as to encompassmodifications and equivalent structures.

At least the following is claimed:
 1. An Unmanned Aerial Vehicle (UAV),comprising: a winch secured to the UAV, the winch including a tether tolower an item from the UAV for delivery; an attachment mechanism toreleasably secure the item to the tether; a flight controller configuredto control a flight path of the UAV and extension of the tether from thewinch; a tether compensation mechanism secured to the UAV; a sensorconfigured to identify at least one component of movement in the tetherwhen the tether is extended from the winch; and a tether responsecontroller configured to: determine a complementary response to themovement in the tether; and direct the tether compensation mechanism tocontact and counterbalance the tether against the movement in the tetheraccording to the complementary response, wherein the flight controlleris further configured to adjust the flight path of the UAV based on thecomplementary response.
 2. The UAV according to claim 1, wherein thetether compensation mechanism comprises: at least one extension armactuator mounted to the UAV at one end; and an aperture mechanismpositioned proximate to another end of the at least one extension armactuator to contact the tether, the tether passing through the aperturemechanism.
 3. The UAV according to claim 1, wherein the tether responsecontroller is further configured to: receive an indication of change inthe flight path of the UAV; and determine the complementary responsebased further on the indication of change in the flight path of the UAV.4. A method to compensate for tether movement in an Unmanned AerialVehicle (UAV), comprising: controlling, by at least one computing deviceof the UAV, a flight path of the UAV; controlling, by the at least onecomputing device of the UAV, extension of a tether from a winch securedto the UAV for delivery of an item; identifying, by at least one sensor,at least one component of movement in the tether; determining, by the atleast one computing device of the UAV, a complementary response to themovement in the tether; directing, by the at least one computing deviceof the UAV, a tether compensation mechanism to contact andcounterbalance the tether against the movement according to thecomplementary response; and adjusting, by the at least one computingdevice, the flight path of the UAV based on the complementary response.5. The method according to claim 4, wherein the tether compensationmechanism comprises: at least one extension arm actuator mounted to theUAV at one end; and an aperture mechanism positioned proximate toanother end of the extension arm actuator, the tether passing throughthe aperture mechanism.
 6. The method according to claim 5, furthercomprising directing the aperture mechanism to clamp the tether based atleast in part on the flight path of the UAV.
 7. The method according toclaim 4, further comprising determining the complementary response basedat least in part on the flight path of the UAV.
 8. The method accordingto claim 4, further comprising: receiving, by the at least one computingdevice of the UAV, an indication of change in the flight path of theUAV; and determining, by the at least one computing device of the UAV,the complementary response based further on the indication of change inthe flight path of the UAV.
 9. The method according to claim 4, furthercomprising determining, by the at least one computing device of the UAV,the complementary response based upon whether the tether is extending orretracting from the winch and a length of extension of the tether fromthe winch.
 10. The method according to claim 4, wherein adjusting theflight path of the UAV comprises adjusting, by the at least onecomputing device, the flight path based further on the movement in thetether.
 11. The method according to claim 4, further comprisingactuating, by the at least one computing device of the UAV, anattachment mechanism to release the item based on a magnitude of tensionin the tether.
 12. An Unmanned Aerial Vehicle (UAV), comprising: a winchsecured to the UAV, the winch including a tether to lower an item fromthe UAV for delivery; a flight controller configured to control flightof the UAV and extension of the tether from the winch; a sensorconfigured to identify at least one component of movement in the tether;and a tether response controller configured to: determine acomplementary response to the movement in the tether; and direct atether compensation mechanism to contact and counterbalance the tetheragainst the movement according to the complementary response, whereinthe flight controller is further configured to adjust the flight of theUAV based on the complementary response.
 13. The UAV according to claim12, wherein the movement comprises at least one of lateral movement andvertical tension components.
 14. The UAV according to claim 12, whereinthe tether compensation mechanism comprises: at least an extension armactuator mounted to the UAV at one end; and an aperture mechanismpositioned proximate to another end of the extension arm actuator, thetether passing through the aperture mechanism.
 15. The UAV according toclaim 14, wherein the tether response controller is further configuredto direct the aperture mechanism to clamp the tether based at least inpart on a flight path of the UAV.
 16. The UAV according to claim 12,wherein the tether response controller is further configured todetermine the complementary response based at least in part on theflight of the UAV.
 17. The UAV according to claim 12, wherein the tetherresponse controller is further configured to: receive an indication ofchange in a flight path of the UAV; and determine the complementaryresponse based further on the indication of change in the flight path ofthe UAV.
 18. The UAV according to claim 12, wherein the tether responsecontroller is further configured to determine the complementary responsebased upon whether the flight controller is extending or retracting thetether from the winch and a length of extension of the tether from thewinch.
 19. The UAV according to claim 12, wherein the flight controlleris further configured to adjust the flight of the UAV based further onthe movement in the tether.
 20. The UAV according to claim 12, furthercomprising an attachment mechanism to releasably secure the item to thetether, wherein the flight controller is further configured to actuatethe attachment mechanism to release the item based on a magnitude oftension in the tether.